Seth Stephen Costello

Seth Stephen Costello, 50, of Rehoboth Beach, Delaware, died on October 30, 2025. Born June 2, 1975, in Phoenixville, Pennsylvania, Seth approached life with integrity, warmth, and an unshakable sense of purpose. He had a rare ability to make those around him feel seen, valued, and supported, and he carried that gift into every role he took on.
Seth was the devoted son of Alice Costello and the late Anthony Costello, and the loving brother of Jonathan and Wes. He was a cherished uncle to Jack, Riley, Emelyn, and Ridgley Costello, and Jack and Reese Barron, delighting in their lives with humor, encouragement, and steady presence. Family was central to Seth, and he nurtured connections across generations with thoughtfulness and care.
An accomplished athlete and businessman, Seth co-captained the Dickinson College football team and graduated in 1997 with a Bachelor of Science in Economics. He combined drive and intellect to excel professionally-first at CoStar Group as National Assistant Director, then in pharmaceutical sales, and later as Chief Operating Officer and Managing Director of Williams Insurance Agency in Rehoboth Beach. A Certified Insurance Counselor, he contributed to the Delaware Insurance Commissioner's Agent Advisory Committee and thirteen other advisory councils, earning respect for his professionalism, insight, and unwavering commitment to excellence.
In Delaware, Seth built a second family among his friends, who knew him as a loyal, generous, and thoughtful presence. He celebrated others' successes, offered guidance without expectation, and approached every day with quiet strength and purpose.
Seth's life was measured not in accolades, but in the lives he touched and the integrity he brought to every relationship. His laughter, generosity, and steadfast example will endure, and those who knew him will carry his memory forward with love, admiration, and gratitude.
In lieu of flowers, donations may be made to the Boys & Girls Clubs of Delaware, supporting youth programs in Sussex County. Visit https://www.bgclubs.org to donate and learn more.
He will be deeply missed.
Please sign the tribute wall located on this site.
A Memorial Service will be held on Friday, November 14, 2025, at 3:00 p.m. at Parsell Funeral Homes and Crematorium, Atkins-Lodge Chapel, 16961 kings Highway Lewes, DE. Visitation will take place from 2:00 to 3:00 p.m. prior to the service.
FLORIST NOTE: PLEASE HAVE ALL FLOWERS DELIVERED ON FRIDAY, NOVEMBER 14, 2025 BY 12PM TO OUR LEWES LOCATION.